The present invention relates to a swash plate type compressor, and in particular to an improvement in a swash plate type compressor for the purpose of reduction of input and output pulsations so as to minimize noise and vibration.
In FIG. 4 of the accompanying drawings there is shown a longitudinal sectional view of a swash plate type compressor of a conventional type, and in FIG. 5 there is shown a sectional view of the compressor of FIG. 4 taken in a plane indicated by the arrows V--V in FIG. 4. The general structure of this compressor will now be explained, along with its deficiencies. For a more detailed description of the basic compressor structure, reference should be made to the section of this specification entitled "DESCRIPTION OF THE PREFERRED EMBODIMENT", which describes the structure of an improved such compressor in detail.
The reference numeral 1 denotes the body of the compressor as a whole; in the following the left hand end thereof in FIG. 4 will be referred to as its front end while its right hand end will be referred to as its rear end. The compressor body 1 is made up of two cylinder blocks 2a, 2b coaxially abutted together, two front and rear valve plates 3a, 3b at the ends of the front and rear cylinder blocks 2a and 2b respectively, a front end block 4a which is secured to the front end of the front cylinder block 2a so as to sandwich the front valve plate 3a thereagainst and so as to define in cooperation therewith chambers as will be explained hereinafter, and a rear end block 4b which is secured to the rear end of the rear cylinder block 2b so as to sandwich the rear valve plate 3b thereagainst and so as to define in cooperation therewith chambers as also will be explained hereinafter.
Rotatably mounted through the front end block 4a, the front valve plate 3a, and the front cylinder block 2a and in a journal formed in the rear cylinder block 2b, along their central axial line, there extends a shaft 6. An obliquely angled swash plate 7 is fixedly mounted on the shaft 6 at the approximate axial center of the shaft 6 between the two valve plates 3a and 3b.
Each of the cylinder blocks 2a and 2b is provided with three respective cylinder bores 10a, 10b, 10c and 10d, 10e, 10f extending parallel to its central axis and arranged around it at positions 120.degree. apart; only one of each of these sets of cylinder bores (10a and 10d) can be seen in FIG. 1 because the other two bores of each set (10b, 10c and 10e, 10f) lie out of the sectional plane of FIG. 4. And the cylinder bores 10a and 10d, 10b and 10e, and 10c and 10f of the front and rear cylinder blocks 2a and 2b are coaxial and oppose one another.
In the cylinder bores 10a and 10d there is slidably fitted a double headed piston member 11a, in the cylinder bores 10b and 10e there is slidably fitted a double headed piston member 11b, and in the cylinder bores 10c and 10f there is slidably fitted a double headed piston member 11c; but only the piston member 11a can be seen in FIG. 4 because the other two piston members 11b and 11c lie out of its sectional plane. A front pumping chamber 14a is defined between the front end of the piston member 11a and the front valve plate 3a, in cooperation with the front cylinder bore 10a; and a rear pumping chamber 14d is defined between the rear end of the piston member 11a and the rear valve plate 3b, in cooperation with the rear cylinder bore 10d. Similarly, front pumping chambers 14b and 14c and rear pumping chambers 14e and 14f are defined by the piston members 11b and 11c and the front and rear valve plates 3a and 3b, in cooperation with the cylinder bores 10b, 10c, 10e, and 10f; but these cannot be seen in FIG. 4. The central part of the piston member 11a is cut away, and two balls 12a, 12b are mounted in the cutaway on opposite axial ends thereof; and via two shoe members 13a and 13b these balls 12a and 12b are engaged with the swash plate 7. The piston member 11a is axially reciprocated to and fro in its cylinder bores 10a and 10d as the shaft 6 and the swash plate 7 are rotated. The arrangements relating to the other two piston members 11b and 11c are similar, but cannot be seen in FIG. 4. Thus, as the shaft 6 is rotated with the swash plate 7 being thereby wobblingly rotated, the three piston members 11a, 11b, and 11c are reciprocally driven to and fro in their cylinder bores, with the phases of their motion differing by 120.degree. from one another; and the six pumping chambers 14a through 14f expand and contract, with the phases of their motion differing by 60.degree. from one another, in an arrangement which will be easily understood based upon the foregoing description.
Each of the six pumping chambers 14a through 14f is provided through its defining valve plate 3a or 3b with an input orifice, respectively denoted as 17a through 17f, and a similarly formed output orifice, respectively denoted as 19a through 19f; the input orifices 17a through 17f are on the sides of the pumping chambers 14a through 14f towards the central axis of the compressor, while the output orifices 19a through 19f are on the opposite sides of said chambers. Fluid flow through each of the output orifices 19a through 19f is controlled by a respective valve means 18a through 18f, only schematically shown in the figures, provided on the respective valve plate 3a or 3b on the outside of the respective pumping chamber 14a through 14f; this valve means 18a through 18f allows fluid to flow out of the respective pumping chamber 14a through 14f through the respective output orifice 19a through 19f, but not in the reverse direction. Similarly, fluid flow through each of the input orifices 17a through 17f is controlled by a valve means not shown in the figures; this valve means allows fluid to flow into the respective pumping chamber 14a through 14f through the respective input orifice 17a through 17f, but not in the reverse direction.
Now, the configurations of the front and the rear end blocks 4a and 4b, along with the chambers and passages defined thereby and their interconnections, will be explained. Each of these members is formed generally in a cup shape, and has a partition wall extending across it, so that in cooperation with the valve plate 3a or 3b to which it is fitted it defines two compartments: an input plenum 15a or 15b, and an output plenum 16a or 16b.
In more detail, the front end block 4a is formed in a manner not specifically shown in any section thereof in the figures, but generally like the rear end block 4b shown in section in FIG. 5 and discussed below, and is generally cup shaped, having a circular rim which is abutted against the end of the front cylinder block 2a and an interior partition wall which defines a front input plenum 15a and a front output plenum 16a formed in a crescent shape surrounding said front input plenum 15a. The front input plenum 15a has the three input orifices 17a, 17b, and 17c of the front pumping chambers 14a, 14b, and 14c opening through the front valve plate 3a into it, and also a front input transfer aperture 21a opens through the front valve plate 3a into said front input plenum 15a. Similarly, the front output plenum 16a has the three output orifices 19a, 19b, and 19c of the front pumping chambers 14a, 14b, and 14c opening through the front valve plate 3a into it, and also a front output transfer aperture not shown in the figures opens through the front valve plate 3a into said front output plenum 16a.
In the cylinder block 2 (i.e. the combination of the front and rear cylinder blocks 2a and 2b) between the pairs of cylinder bores 14b, 14e and 14c, 14f there is defined an input transfer chamber 22 extending right through the cylinder block 2 and communicating with the front input plenum 15a via the front input transfer aperture 21a through the front valve plate 3a at its front end, and, as will be seen, with the rear input plenum 15b via a rear input transfer aperture 21b through the rear valve plate 3b at its rear end; and similarly between the pairs of cylinder bores 14a, 14d and 14b, 14e there is defined an output transfer passage extending right through the cylinder block 2 and communicating at its front end with the front output plenum 16a via the aforementioned front output transfer aperture formed through the front valve plate 3a, and with the rear output plenum 16b via a rear output transfer aperture 42 through the rear valve plate 3b at its rear end, but none of these arrangements can be seen in the figures.
Now, referring to FIG. 5, there is shown a transverse cross section of the rear end block 4b looking towards the rear valve plate 3b. This rear end block 4b is generally cup shaped, having a circular rim which is abutted against the end of the rear cylinder block 2b and an interior partition wall which defines a rear input plenum 15b and a rear output plenum 16b formed in a crescent shape surrounding said rear input plenum 15b. The rear input plenum 15b has the three input orifices 17d, 17e, and 17f of the rear pumping chambers 14d, 14e, and 14f opening through the rear valve plate 3b into it, and also a rear input transfer aperture 21b opens through the rear valve plate 3b into said rear input plenum 15b. Similarly, the rear output plenum 16b has the three output orifices 19d, 19e, and 19f of the rear pumping chambers 14d, 14e, and 14f opening through the rear valve plate 3b into it, and also a rear output transfer aperture 42 opens through the rear valve plate 3b into said rear output plenum 16b.
Thus, the front and rear input plenums 15a and 15b are communicated together through the front input transfer aperture 21a, the input transfer chamber 22, and the rear input transfer aperture 21b; and the front and rear output plenums 16a and 16b are communicated together through the front output transfer aperture (not shown), the output transfer passage (also not shown), and the rear output transfer aperture 42. An inlet 32 is provided into the rear input plenum 15b, and an outlet not shown in the figures is provided out of the rear output plenum 16b, and pipes, not shown, are connected to this inlet and outlet so as to supply and exhaust fluid, for example refrigerant for an automobile air conditioner, or the like.
Therefore, during operation of the compressor described above as the shaft 6 and the swash plate 7 rotate and the six pumping chambers 14a through 14f expand and contract with the phases of their motions being 60.degree. apart as explained above, fluid enters the inlet 32 and passes into the rear input plenum 15b. This flow then splits: approximately half of it proceeds through the rear input transfer aperture 21b and down the input transfer chamber 22 to pass from its front end via the front input transfer aperture 21a through the front valve plate 3a into the front input plenum 15a, and is then supplied to the three input orifices 17a, 17b, and 17c opening through the front valve plate 3a for the front pumping chambers 14a, 14b, and 14c (past the input valve means therefor, not shown), and thus is sucked into these front pumping chambers 14a, 14b, and 14c in turn as the pistons 11a through 11 c reciprocate. Similarly, the other approximate half part of said flow is supplied directly from the rear input plenum 15b to the three input orifices 17d, 17e, and 17f opening through the rear valve plate 3b for the rear pumping chambers 14d, 14e, and 14f (also past the input valve means therefor, not shown), and thus is sucked into these rear pumping chambers 14d, 14e, and 14f in turn as the pistons 11a through 11c reciprocate.
Next, to describe the outlet side, with regard to the flow of the fluid which has been compressed within the rear pumping chambers 14d, 14e, and 14f, it is ejected therefrom directly into the rear output plenum 16b, through the rear output orifices 19d, 19e, and 19f formed in the front valve plate 3a, past the output valve means 18d, 18e, and 18f respectively. And the flows of the fluid which has been compressed within the front pumping chambers 14a, 14b, and 14c pass respectively through the front output orifices 19a, 19b, and 19c formed in the front valve plate 3a, past the output valve means 18a, 18b, and 18c respectively, into the front output plenum 16a, where they meld together into a front output fluid flow. This fluid flow then flows from said front output plenum 16a through the aforementioned front output transfer aperture (not shown) formed through the front valve plate 3a, into the front end of the output transfer passage (also not shown) defined between the pairs of cylinder bores 14a, 14d and 14b, 14e and axially extending right through the cylinder block 2, down along this output transfer passage to the rear end thereof, and through the rear output transfer aperture 42 formed in the rear valve plate 3b into the rear output plenum 16b, to become melded with the aforementioned three flows of fluid from the rear pumping chambers 14d, 14e, and 14f which have also passed into said rear output plenum 16b. Finally, these united output flows of all the six pumping chambers 14a through 14f pass out of the rear output plenum 16b through the fluid outlet (not shown) and into the output pipe (also not shown) connected thereto.
However, the problem with this structure is that, as the six pumping chambers 14a through 14f one after another in sequence suck in fluid through their respective input orifices 17a through 17f and expel fluid under pressure through their respective output orifices 19a through 19f, pressure pulsations are generated at the other sides both of these input and these output orifices. Such pressure pulsations are easily transmitted through the inlet 32 and the outlet (not shown) to the pipes connected thereto, and can cause problems with regard to noise and vibration. Such vibration can be very troublesome, possibly leading to deterioration of the mounting of the pipes and failure of the system to which the compressor is fitted.